Computer systems increasingly rely on faster data transfer between individual microelectronic circuits. Recently, silicon microelectronic circuits have become available with tens to hundreds of input and output channels operating at speeds exceeding 10 gigabits per second each. These may include FPGAs, CPUs, and digital switching fabric chips, in particular. Considerable electrical power may be required to drive individual input/output channels, in particular in situations where the channels include long printed circuit board traces and/or long cables.
Recent advances in silicon photonics enable the use of optical interconnects between electronic circuits. Optical interconnects can support very high data transfer rates. Individual optical channels are currently be modulated at rates reaching 40 gigabits per second and higher. Wavelength division multiplexing (WDM) may be used to provide multiple wavelength channels in a single optical fiber, and a plurality of optical fibers may be used to provide even more bandwidth.
Optical interconnects must provide, for each wavelength channel, modulation and electro-optical conversion at the transmitter end and demodulation and optoelectronic data conversion at the receiver end of a communication link. To provide this functionality prior to this invention, an optical interconnect may require multiple separate devices such as modulators, detectors, drivers, lasers, etc. The resulting optical interconnects are often bulky, complex, costly, and may draw considerable amounts of electrical energy to operate, negating many advantages of optical interconnects. Furthermore, as with many fiber-based optical devices, active alignment of optical fibers may be required. Active optical alignment is time-consuming, and therefore expensive in mass production.